(a) Field of the Invention
The present invention relates to a display device and a method of testing a sensing unit of the display device. More particularly, the present invention relates to a display device having a sensing unit and a method of testing the sensing unit in an easy manner.
(b) Description of the Related Art
A general liquid crystal display (“LCD”) of a display device includes two display panels having pixel electrodes and a common electrode, and a liquid crystal layer having dielectric anisotropy interposed between the two display panels.
The pixel electrodes are arranged in a matrix form. Further, the pixel electrodes are connected to switching elements such as thin film transistors (“TFTs”), and are sequentially supplied with an image data voltage.
The common electrode is formed over the entire surface of a display panel, and is supplied with a common voltage. In terms of a circuit configuration, a pixel electrode, a common electrode, and a liquid crystal layer interposed there between form a liquid crystal capacitor. The liquid crystal capacitor is a basic unit for constituting a pixel along with a switching element connected thereto.
In the LCD, an electric field is generated in the liquid crystal layer while a voltage is supplied to the two electrodes. By controlling intensity of the electric field, the transmittance of light passing through the liquid crystal layer is regulated, thereby obtaining a desired image.
A touch screen panel is defined as a device in which a picture or a drawing is written or drawn by bringing a finger or a pen into contact with a screen, or a desired command is executed in a machine such as a computer by executing an icon. The LCD having a touch screen panel attached thereon can recognize not only whether a user's finger or a touch pen comes in contact with the screen, but also contact position information.
During manufacture, a visual inspection (“VI”) is carried out so as to test a sensing unit embedded in the LCD and a signal line or the like connected to the sensing unit. However, since an additional test device is required for this, there are costs associated therewith, and the test operation is complex.